Numerical Simulation And Experimental Study On Laser Welding Of Thick Plate And High Strength Steel

In the manufacturing process of shipbuilding,power generation equipment,machine tools,petrochemical,marine engineering,aerospace and so on,the welding problems of thick wall members appear frequently.At present,the narrow gap multilayer welding of 70 mm thick B950 CF hydropower steel is realized by single side laser wire filler welding.In order to optimize the distribution of residual stress and reduce the deformation of welding,this paper uses double-sided welding to weld the narrow gap welded joint of 70 mm low alloy steel and carries out the corresponding welding process test.Compared with the thin plate,the residual stress distribution of the thick plate is more complex,and the residual stress inside the thick plate is difficult to be obtained.Therefore,the finite element software ABAQUS is used to simulate the welding process of the welded joints obtained by double side welding and single side welding.The residual stress distribution laws under the two ways are obtained and compared.The main work is as follows:(1)The welding process of 70 mm thick plate narrow gap low alloy steel double side welding process is investigated,and a reasonable welding process is obtained.Metallographic analysis of welded joint is carried out,and the microstructure of the joint is good.(2)Using the finite element software,ABAQUS,a finite element model of 70 mm thick plate narrow gap low alloy steel double-sided welding and single face welding joint is established.The numerical simulations of the double side welding and the single side welding of 70 mm thick plate and narrow gap low alloy steel are carried out.The residual stress distribution of double side welding and single side welding is obtained.(3)Compared with the single side welding,the transverse residual stress and the longitudinal residual stress are greater,but the angle deformation of the double side welding is smaller,and the equivalent residual stresses is smaller.The residual stress of the double welded joint is tested by the X ray diffraction method.The residual stress on the surface of the specimen is obtained.It is compared with the results of numerical simulation,and thereliability of the simulation is verified by the reference.The 70 mm double plate welding technology for thick plate narrow gap low alloy steel is applied in this paper,which solves the engineering problem of large plate welding distortion in actual production.The simulated residual stress distribution of single side and double-sided welding is of positive significance to further study of the distribution,control and elimination of welding residual stress.